Continuity mistake: When Batman is removing the part of the wall with the bullet in it, we see the bullet hole is off-center, to the left side of the block that Batman carves out. In the next scene where we see the mounted gun shooting specialized bullets into blocks, Bruce compares the block he removed from the apartment, which is in a plastic bag, to the holes left in the sample blocks. The hole in the block from the apartment is now in the center of the block, not on the left side as it was when he removed it.
Picture added by ployp
To submit a picture, just click the edit icon under the relevant entry, then choose 'add a picture'. Thanks!
All images remain the copyright of their original owners - these low resolution images are simply individual frames used to demonstrate the entry.